As described in Patent Document 1, it is common that, in a machine for making plastic bags, the machine comprises a longitudinal heater, a cross heater and a cutter by which plastic films are heat sealed with each other longitudinally and widthwise thereof and cross cut widthwise, to successively make plastic bags. The plastic bags are then discharged successively. In the machine described in Patent Document 1, when the plastic bags are discharged, a predetermined number of the plastic bags are stacked and then fed.
Hereinafter, the machine of Patent Document 1 will be described. A plurality of catcher bars is opposite to a discharge position of the plastic bags above a feed conveyor. The catcher bars are spaced from each other and arranged in a lateral direction. A plurality of shutter bars is further disposed between the discharge position of the plastic bags and the catcher bars. The shutter bars are extended vertically and spaced from each other in the lateral direction. It should be understood that the lateral direction denotes a horizontal direction normal to the discharge direction. Thus, when the plastic bags are discharged, the plastic bags collide against the shutter bars so as to fall and stack on the feed conveyor. In addition, the catcher bars pass through between the shutter bars and protrude toward the discharge position of the plastic bags. The catcher bars receive coming plastic bags after the plastic bags are stacked. Then, the plastic bags are fed by the feed conveyor, and the catcher bars are retracted to their original position so that the coming plastic bags can fall onto the feed conveyor.
Therefore, a predetermined number of the plastic bags can be stacked on and then fed by the feed conveyor. However, there is a problem according to the type of the plastic bag. In case that the plastic films are heat sealed with each other longitudinally and widthwise thereof and cross cut widthwise so as to successively make the plastic bags, the plastic bags have a relatively high stiffness so as not to be very flexible. Thus, the plastic bags can fall onto the feed conveyor so as to be stacked on and then fed by it. However, the plastic bags do not always have a relatively high stiffness.
As described in Patent Document 2, for example, the plastic films are heat cut by a heat blade widthwise thereof, for making the plastic bags. The plastic bags are flexible to have a low stiffness. Therefore, in the machine of Patent Document 1, it is inappropriate that the plastic bags fall onto the feed conveyor so as to be stacked on and then fed by it. Because, there is a problem that the plastic bags may easily be out of alignment, slid and collapsed while being stacked on and then fed by the feed conveyor.
The machine of Patent Document 1 can stack and feed not only the plastic bags but also other sheet products discharged successively, but there is the same problem in feeding the sheet products which have a low stiffness, as described above.
It is, therefore, an object of the invention to provide an apparatus for stacking and feeding the sheet products discharged successively from a discharge position, in which the sheet products can be stacked and then fed reliably even though the sheet products have a low stiffness.
Patent Document 1: JP B5439611
Patent Document 2: JP A62-244864